The present invention relates to a branding device which is useful, for example, for marking the date of manufacture on containers containing food or beverage.
FIG. 8 shows such a device heretofore known which comprises a holder 80 and type blocks 81 removably attached to the holder 80. The holder 80 is in the form of a horizontally elongated rectangular parallelepipedal block made of a metal, such as copper alloy, having good heat conductivity. The holder 80 has two rectangular parallelepipedal type block holding cavities 82 which are horizontally elongated, opened toward the front and arranged longitudinally of the holder, and a heater insertion bore 83 extending through the holder 80 longitudinally thereof. An L-shaped NICHROME wire heater 85 is inserted at its horizontal portion in the bore 83. A plurality of type blocks 81, each in the form of a rectangular to square bar, are arranged side by side horizontally as inserted in each cavity 82, with the forward ends of the type blocks 81 projecting forward beyond the holder 80. A type locking rod 86 bent like a crank is removably attached to the holder 80, whereby the type blocks 81 are removably retained in the holder 80 although a detailed description will not be given.
With the device described above, the holder 80 is heated by the heater 85, and the type blocks 81 are heated with the heat transmitted thereto from the holder 80. Thus, the holder 80 which has an exceedingly greater heat capacity than the type blocks 81 is maintained at a high temperature so as to diminish the variation in the temperature of the type blocks 81 during branding operation. However, the device has the following problems. First, the holder 80 releases a large amount of heat, hence a great heat loss. Second, heat is transferred from the heater 85 to the type blocks 81 through the holder 80, so that the heater 85 needs to produce such an amount of heat as to give a temperature which is higher than the temperature of the type blocks 81 required for branding by an amount corresponding to the heat transfer loss. This is likely to shorten the life of the heater 85. Third, the holder 80 having a high temperature and left exposed is likely to contact the worker to cause a burn, hence a safety problem.